by The Editorial Board, USA TODAY

by The Editorial Board, USA TODAY

By almost any measure, the National Football League is enjoying another extraordinary year. During the 17-week NFL regular season, the 22 highest-rated shows on television were NFL games. And roughly 155 million people, or half the U.S. population, are expected to watch at least some of Sunday's Super Bowl.

So it is with good reason that owners and league officials gathering in New Orleans this weekend should be in good cheer. The NFL, in the parlance of business, is killing it.

Underneath the glitter and spectacle, however, the NFL's $9 billion business faces a significant long-term threat. With scientific studies increasingly linking head injuries with degenerative brain diseases, fans and young people could turn away from the sport, and lawsuits already filed by former players could result in huge liabilities.

To its credit, the league appears to recognize the risks. Under Commissioner Roger Goodell, it has taken a series of safety-related steps in the face of carping by players, ex-players and commentators who say the sport is being sissified.

The league is right to impose new penalties and fines on violent hits. It is right to punish participants in a bounty system that rewarded players for injuring their opponents. It is right to insist that players with concussions aren't rushed back on to the field. And it is right to consider further changes to the rules and to explore new helmet technologies.

These are the types of things that responsible franchise owners do to protect their people and businesses.

Baltimore Ravens safety Bernard Pollard had things backwards when he said the NFL could be gone in 30 years as the result of unpopular new rules. The biggest threat to the NFL is not that hard-core fans will turn away because of these rules, but that more marginal fans will turn away because of the violence that the rules are meant to address.

Football already has a reputation as a kind of crapshoot, with injuries playing a major role in teams' fortunes and players' long-term health. It might soon earn the reputation as a sport that young athletes in much of the country avoid. President Obama says that if he had sons, he'd hesitate to let them play football, a view shared by millions of parents across America.

These are not developments consistent with football remaining "America's game." And if a player dies as the result of an on-field injury - something that is not unthinkable given the size and speed of today's players and the glorification of bone-jarring hits, which on rare occasions have left players paralyzed - the game would go through a period of soul searching.

While a downturn in football's popularity as the result of its violent nature might seem far-fetched, the same could have been said about boxing. Once one of the nation's premier sports, boxing is now regarded as a brutal niche.

As the NFL community gathers for the Super Bowl, it has every reason to be happy about the incredible success of its undertaking. But it is also appropriately worried about what might lie over the horizon. Owners would be wise to consider the counsel that their coaches often give their players: Just because you are successful now doesn't mean you should take your future success for granted.